This paper proposes a design and implementation of the bi-directional DC-DC converter for Wind Energy Conversion System. The proposed project consists of boost DC/DC converter, bi-directional DC/DC converter (BDC), pe...This paper proposes a design and implementation of the bi-directional DC-DC converter for Wind Energy Conversion System. The proposed project consists of boost DC/DC converter, bi-directional DC/DC converter (BDC), permanent magnet DC generator and batteries. A DC-DC boost converter is interface with proposed wind system to step up the initial generator voltage and maintain constant output voltage. The fluctuation nature of wind makes them unsuitable for standalone operation. To overcome the drawbacks an energy storage device is used in the proposed system to compensate the fluctuations and to maintain a smooth and continuous power flow in all operating modes to load. Bi-directional DC-DC converter (BDC) is capable of transforming energy between two DC buses. It can operate as a boost converter which supplies energy to the load when the wind generator output power is greater than the required load power. It also operates in buck mode which charges from DC bus when output power is less than the required load power. The proposed converter reduces the component losses and increases the performance of the overall system. The complete system is implemented in MATLAB/SIMULINK and verified with hardware.展开更多
Major problem with grid tied micro wind turbine is synchronization and wind variability. Due to this problem the stability of available grid gets reduced. The stability can be achieved by output power control of the t...Major problem with grid tied micro wind turbine is synchronization and wind variability. Due to this problem the stability of available grid gets reduced. The stability can be achieved by output power control of the turbine. Major part of many countries like India, the annual mean wind speed is not high. The rated wind speed of turbine remain around 11 m/s and cut in is around 3.5 m/s. Due to this problem we aimed to develop a sustainable wind energy system that can provide stable power supply even at the locations of low wind speed of 2 - 4 m/s. To address this issue, a momentary impulse or external torque to the rotor by external motor is one of the good options to maintain the momentum of blades and thus provide stability for sufficient time. Various theoretical calculations and experiments are conducted on the above method. This would increase the output power and also the efficiency of wind turbine. We show that Return-On-Investment will be high as compared with other grid connected turbines. Our proposed concept in the present study, if implemented properly, can help the installation of number of wind turbines even at domestic level. It also makes the consumers energy independent and promotes the use of wind as a source of energy and may enter as a rooftop energy supply system similar to solar.展开更多
串联型汇集送出方案被认为是规模化远海风电全直流系统最可能实现的方案。为避免串联型直流风电机组因风电机组间耦合特性引起的过电压现象和风功率损失,使系统实现高压直流送出和具备直流故障自清除能力,提出了基于容性能量转移原理DC...串联型汇集送出方案被认为是规模化远海风电全直流系统最可能实现的方案。为避免串联型直流风电机组因风电机组间耦合特性引起的过电压现象和风功率损失,使系统实现高压直流送出和具备直流故障自清除能力,提出了基于容性能量转移原理DC/DC变换器(capacitive energy transfer principle based DC/DC transformer, CETDCT)的新型串联系统。该系统拓扑中海上升压站为CET-DCT结构,并采用基于混合型模块化多电平换流器(modular multilevel converter, MMC)的直流风电机组和岸上换流站。以实现风电机组全工况下的最大功率点跟踪、穿越多种直流故障为目标,设计了系统的控制与保护策略。基于PSCAD/EMTDC搭建了传统串联系统和新型串联系统的仿真模型。对传统串联系统风电机组间功率不平衡工况的仿真,验证了风电机组的过电压和风功率损失现象。对新型串联系统稳态工况和故障工况的仿真,验证了新型串联系统的运行特性及所提策略的有效性。展开更多
针对风电全直流系统并网给交流电网带来的系统惯量降低、调频能力不足等问题,提出一种改善惯性响应与一次调频的变系数风电全直流系统协调控制策略。在惯量响应方面,网侧换流站采用惯性同步控制,直流升压站采用恒变比控制,实现直流电容...针对风电全直流系统并网给交流电网带来的系统惯量降低、调频能力不足等问题,提出一种改善惯性响应与一次调频的变系数风电全直流系统协调控制策略。在惯量响应方面,网侧换流站采用惯性同步控制,直流升压站采用恒变比控制,实现直流电容对电网的惯量支撑及直流低压侧的直流电压对交流系统频率的感知,在此基础上对直流风电机组(direct current wind turbine,DCWT)附加变虚拟惯性系数的虚拟惯量控制,使风电全直流系统在不同频率响应阶段具备不同的等效惯量。在一次调频方面,DCWT采用超速与变桨相结合的减载运行方式,通过变下垂控制来改变其有功出力,充分利用不同风速下的备用容量,使风电全直流系统更有效地参与一次调频。仿真算例表明,文中所提策略改善了风电全直流系统接入后电力系统的惯性响应及一次调频。展开更多
Over the last few years, smart grids have become a topic of intensive research, development and deployment across the world. This is due to the fact that, through the smart grid, stable and reliable power systems can ...Over the last few years, smart grids have become a topic of intensive research, development and deployment across the world. This is due to the fact that, through the smart grid, stable and reliable power systems can be achieved. This paper presents a fuzzy logic control for dual active bridge series resonant converters for DC smart grid application. The DC smart grid consists of wind turbine and photovoltaic generators, controllable and DC loads, and power converters. The proposed control method has been applied to the controllable load＇s and the grid side＇s dual active bridge series resonant converters for attaining control of the power system. It has been used for management of controllable load＇s state of charge, DC feeder＇s voltage stability during the loads and power variations from wind energy and photovoltaic generation and power flow management between the grid side and the DC smart grid. The effectiveness of the proposed DC smart grid operation has been verified by simulation results obtained by using MATLAB and PLECS cards.展开更多
This paper analyzed the operating principles and power and torque characteristics of the wind turbine and the direct current motor (DC motor), and investigated the operating characteristics of the wind turbine compare...This paper analyzed the operating principles and power and torque characteristics of the wind turbine and the direct current motor (DC motor), and investigated the operating characteristics of the wind turbine compared to that of the DC motor. The torque imitation scheme, which has good performance and high feasibility, together with the whole wind turbine imitation system, was provided. The wind turbine imitation system includes not only a hardware platform composed of PC, data-collection board and thyristor-based velocity-regulator, but also monitor software of wind turbine imitation. The experimental results of different occasions verify the correctness and feasibility of the wind turbine imitation scheme proposed in this paper, which provided a valid idea for wind turbine imitation and investigation of wind power generation techniques in the laboratory.展开更多
文摘This paper proposes a design and implementation of the bi-directional DC-DC converter for Wind Energy Conversion System. The proposed project consists of boost DC/DC converter, bi-directional DC/DC converter (BDC), permanent magnet DC generator and batteries. A DC-DC boost converter is interface with proposed wind system to step up the initial generator voltage and maintain constant output voltage. The fluctuation nature of wind makes them unsuitable for standalone operation. To overcome the drawbacks an energy storage device is used in the proposed system to compensate the fluctuations and to maintain a smooth and continuous power flow in all operating modes to load. Bi-directional DC-DC converter (BDC) is capable of transforming energy between two DC buses. It can operate as a boost converter which supplies energy to the load when the wind generator output power is greater than the required load power. It also operates in buck mode which charges from DC bus when output power is less than the required load power. The proposed converter reduces the component losses and increases the performance of the overall system. The complete system is implemented in MATLAB/SIMULINK and verified with hardware.
文摘Major problem with grid tied micro wind turbine is synchronization and wind variability. Due to this problem the stability of available grid gets reduced. The stability can be achieved by output power control of the turbine. Major part of many countries like India, the annual mean wind speed is not high. The rated wind speed of turbine remain around 11 m/s and cut in is around 3.5 m/s. Due to this problem we aimed to develop a sustainable wind energy system that can provide stable power supply even at the locations of low wind speed of 2 - 4 m/s. To address this issue, a momentary impulse or external torque to the rotor by external motor is one of the good options to maintain the momentum of blades and thus provide stability for sufficient time. Various theoretical calculations and experiments are conducted on the above method. This would increase the output power and also the efficiency of wind turbine. We show that Return-On-Investment will be high as compared with other grid connected turbines. Our proposed concept in the present study, if implemented properly, can help the installation of number of wind turbines even at domestic level. It also makes the consumers energy independent and promotes the use of wind as a source of energy and may enter as a rooftop energy supply system similar to solar.
文摘串联型汇集送出方案被认为是规模化远海风电全直流系统最可能实现的方案。为避免串联型直流风电机组因风电机组间耦合特性引起的过电压现象和风功率损失,使系统实现高压直流送出和具备直流故障自清除能力,提出了基于容性能量转移原理DC/DC变换器(capacitive energy transfer principle based DC/DC transformer, CETDCT)的新型串联系统。该系统拓扑中海上升压站为CET-DCT结构,并采用基于混合型模块化多电平换流器(modular multilevel converter, MMC)的直流风电机组和岸上换流站。以实现风电机组全工况下的最大功率点跟踪、穿越多种直流故障为目标,设计了系统的控制与保护策略。基于PSCAD/EMTDC搭建了传统串联系统和新型串联系统的仿真模型。对传统串联系统风电机组间功率不平衡工况的仿真,验证了风电机组的过电压和风功率损失现象。对新型串联系统稳态工况和故障工况的仿真,验证了新型串联系统的运行特性及所提策略的有效性。
文摘针对风电全直流系统并网给交流电网带来的系统惯量降低、调频能力不足等问题,提出一种改善惯性响应与一次调频的变系数风电全直流系统协调控制策略。在惯量响应方面,网侧换流站采用惯性同步控制,直流升压站采用恒变比控制,实现直流电容对电网的惯量支撑及直流低压侧的直流电压对交流系统频率的感知,在此基础上对直流风电机组(direct current wind turbine,DCWT)附加变虚拟惯性系数的虚拟惯量控制,使风电全直流系统在不同频率响应阶段具备不同的等效惯量。在一次调频方面,DCWT采用超速与变桨相结合的减载运行方式,通过变下垂控制来改变其有功出力,充分利用不同风速下的备用容量,使风电全直流系统更有效地参与一次调频。仿真算例表明,文中所提策略改善了风电全直流系统接入后电力系统的惯性响应及一次调频。
文摘Over the last few years, smart grids have become a topic of intensive research, development and deployment across the world. This is due to the fact that, through the smart grid, stable and reliable power systems can be achieved. This paper presents a fuzzy logic control for dual active bridge series resonant converters for DC smart grid application. The DC smart grid consists of wind turbine and photovoltaic generators, controllable and DC loads, and power converters. The proposed control method has been applied to the controllable load＇s and the grid side＇s dual active bridge series resonant converters for attaining control of the power system. It has been used for management of controllable load＇s state of charge, DC feeder＇s voltage stability during the loads and power variations from wind energy and photovoltaic generation and power flow management between the grid side and the DC smart grid. The effectiveness of the proposed DC smart grid operation has been verified by simulation results obtained by using MATLAB and PLECS cards.
基金supported by the Hi-Tech Research and Development Program of China (No.2001AA512023).
文摘This paper analyzed the operating principles and power and torque characteristics of the wind turbine and the direct current motor (DC motor), and investigated the operating characteristics of the wind turbine compared to that of the DC motor. The torque imitation scheme, which has good performance and high feasibility, together with the whole wind turbine imitation system, was provided. The wind turbine imitation system includes not only a hardware platform composed of PC, data-collection board and thyristor-based velocity-regulator, but also monitor software of wind turbine imitation. The experimental results of different occasions verify the correctness and feasibility of the wind turbine imitation scheme proposed in this paper, which provided a valid idea for wind turbine imitation and investigation of wind power generation techniques in the laboratory.
